He stood with President Clinton last Thursday to unveil a $950 million police initiative. Earlier in the week, he pledged to press Congress on the thorny problem of out-of-state trash and posed with Vice President Gore to accept $100 million in federal redevelopment aid.

But on impeachment, the drama that has besieged Washington, Sen. Charles S. Robb (D-Va.) has been conspicuously quiet.

As the Senate plunges ahead with the trial of the president, Maryland's and Virginia's senators  three Democrats, one Republican  are grappling with their constitutional duty while carefully assessing the potential political costs.

None of the lawmakers seems likely to buck their parties. Yet the junior senator from Virginia, gearing up to run for a third term next year, appears likeliest to face consequences however he votes, according to campaign strategists. At a time when Robb planned to bolster his reelection chances against announced GOP challenger, George Allen, by focusing on popular programs, the president's problems instead threaten to remind voters of Robb's own past missteps.

For Robb, there are eerie echoes in Clinton's sexual involvement with former White House intern Monica S. Lewinsky, which has imperiled his presidency with impeachment charges of perjury and obstruction of justice. Robb's 1994 race against Iran-contra figure Oliver L. North was rocked by allegations of an affair with former Miss Virginia, Tai Collins.

Both men denied having an affair but ultimately acknowledged behavior that wasn't "appropriate" for a married man. Both apologized to their wives. And both adopted a strict, if tortuous, definition of infidelity that included "coital relations" but not oral sex.

Robb faced down the adultery allegations, as well as an accusation that he was involved in releasing an illegally taped telephone conversation of a political rival, in part by insisting that he had "never told a lie." He contrasted his behavior with that of North, the former Marine colonel who was convicted of lying to Congress in its arms-for-hostages investigation. The conviction was overturned on appeal.

Ironically, Charles F.C. Ruff, the attorney who successfully represented Robb in a grand jury probe of the taping incident, is now Clinton's White House counsel.

Robb, a former governor, won a three-way Senate race with 46 percent of the vote in 1994 and had hoped the decade-old controversy would be ancient history in any showdown with Allen, also a former governor.

Virginia Republicans, however, last week signaled that "truth telling" will be an issue in the Senate contest  and tried to tie Robb to Clinton's sex and perjury case.

"Senator Robb campaigned on the importance of telling the truth, saying individuals who didn't tell the truth shouldn't hold office," Virginia Sen. J. Randy Forbes (Chesapeake), chairman of the state Republican Party, said in an interview last week. "Clearly, now you have a president who didn't tell the truth under his oath of office," and Robb's continued silence in the Clinton matter is a "huge double standard."

Democrats say the GOP is waging another attack of innuendo to malign Robb personally, just as the Republican-controlled Congress has pilloried a popular president.

"Let's get out of the shadows and say to the people that the George Allen strategy is to try to run a smear campaign," said Virginia Del. Kenneth R. Plum (Fairfax), the state's Democratic Party chairman. "Republicans spent $40 million and two years to smear the president nationally. Now we're seeing the beginning of a two-year effort to smear the senator of Virginia. Chuck Robb has done nothing but his duty as a senator."

At this point, Robb is alone among the region's senators in refusing to discuss his views on impeachment. "It's a solemn responsibility," he has said, "and I'm going to approach it that way."

Sen. Barbara A. Mikulski (D-Md.), who was swept to reelection in November and won't face voters again until 2004, and Sen. Paul S. Sarbanes (D-Md.), who must run in 2000, have called for a shortened trial. Mikulski has stated that she might not vote to remove Clinton even if the charges against him are proved  if they do not "gravely" harm the Constitution.

In strongly Democratic Maryland, both lawmakers are in a "no-lose" situation in defending Clinton, said pollster Brad Coker, of Mason-Dixon Political/Media Research. But the case in Virginia, he said, is less clear-cut.

Sen. John W. Warner (R-Va.) last week dismissed questions about the political consequences of the impeachment trial, saying, "Politics be damned." Neither he nor party rivals seem eager for a rematch of the angry 1996 primary challenge Warner faced after he declared North an unfit GOP nominee.

"You know my feelings about John Warner," said Michael P. Farris, a conservative Republican who lost a 1993 bid for Virginia lieutenant governor after Warner declined to endorse him. But "he'll probably be pretty straight up and decide his vote on what the evidence will show."

For both state parties, using the impeachment issue as a political wedge is fraught with risk, analysts said.

Even in GOP-friendly Virginia, voters appear to share the national revulsion against the impeachment trial. According to a recent poll in the Richmond Times-Dispatch, 55 percent of the state's voters oppose removing Clinton, and 39 percent favor his ouster. The same survey, which had a margin of error of plus or minus 4 percentage points, showed that Clinton's approval rating is just as high as it is nationwide, 65 percent.

"Both parties have a problem here," said political analyst Stuart Rothenberg, whose Washington newsletter, this week, will rate Robb as the sole incumbent Democratic senator vulnerable in 2000.

"If Republicans try to dredge up all the questions about Chuck Robb's past behavior, it's difficult and dangerous because of sensitivity about political character assassination," he said. "On the other hand, questions about character and integrity are part of the soft underbelly of Robb."

Allen, now a prominent lawyer in Richmond, led Robb by 47 percent to 38 percent in the same survey, and analysts expect the Senate race to be close. Like Robb, Allen has declined to answer questions about the president's impeachment trial.

Left unsaid is the assumption that Robb will never vote to impeach a president who rallied support for him five years ago  and risk losing his own base of Democratic supporters.

For now, he is eager to focus on his work, and aides say he will concentrate this year on defense, Social Security and Medicare issues.

"If Clinton can weather the much more problematic [charge] that he lied under oath about [his personal life], it may well be that the public really doesn't vote on these kinds of matters," Richmond political scientist Robert D. Holsworth said.

Mindful of voter backlash, Forbes echoed Allen aide Jay Timmons, saying the party's emphasis on telling the truth is not a personal attack, which both ruled out for the campaign. "The Republican Party doesn't believe in attacking people on personal issues such as that," Forbes said.

Even state Republican Party Executive Director Chris LaCivita, who charged last fall that Robb's silence on the Lewinsky matter condoned "sick behavior on the part of the president," is holding his tongue. "That was then. This is now," he said.

Thomas J. Lehner, Robb's chief of staff, said his boss "knows that the public has had enough of this kind of thing and that it's important to restore some dignity and honor to the process."